GAC ESD-5550 Series Manual - Page 8

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SySTEM TROUblESHOOTINg (CONTINUED)

InSTaBILITY

SYmPTom

Fast Periodic

The engine seems

to jitter with a 3Hz

or faster irregularity

of speed.

Slow Periodic

An irregularity

of speed below

3Hz. (Sometimes

severe)

Non-Periodic

Erratic Engine

Behavior

UnSaTISfacTorY Performance

SYmPTom

Engine Overspeeds

Overspeed Shuts Down En-

gine After Running Speed is

Reached

Overspeed Shuts Down En-

gine Before Running Speed

is Reached

Actuator does not energize

fully

Engine remains below

desired governed speed

Readjust the GAIN and STABILITy for optimum control.

Turn off any local electrical equipment that may be causing EMI interference.

Set the Lead Circuit DIP switch SW1 to OFF

If system is still unstable, set Soft Coupling SW2 to ON. This may indicate soft or worn couplings in drive

train.

Remove E1 to E2 jumper. See section 4, Wiring diagram.

Readjust GAIN and STABILITy

Set Lead Circuit and Soft Coupling DIP switches SW1 and SW2 to ON in the following order: First SW1,

Second SW2, and Third SW1 & SW2.

Check fuel system linkage during engine operation for:

•

binding

•

high friction

•

poor linkage

Adjust DEAD TIME COMPENSATION by adding a capacitor from posts E1 to E2. See section 4, Wiring

diagram. Start with 10 mF and increase until instability is eliminated.

Add small amount of droop (jumper K and L). See section 4, Wiring diagram.

If increasing GAIN does not reduce the instability but not totally correct it issue may be with engine.

If this is the case, there is most likely a problem with the engine itself. Check for:

•

engine mis-firings

•

an erratic fuel system

•

load changes on the generator set voltage regulator.

If throttle is slightly erratic, but performance is fast, move SW1 to the OFF position.

normaL reaDInG

Do Not Crank. Apply DC power to

the governor system.

Manually hold the engine at the

desired running speed. Measure

the DC voltage between Terminals

A(-) & F(+) on the speed control

unit.

Check impedance between

Terminals C & D. Should be 160

to 1200 Ω

Measure the voltage at the battery

while cranking.

Momentarily connect Terminals A

and F. The actuator should move

to the full fuel position.

Measure the actuator output, Ter-

minals A & B, while running under

governor control.

ProBaBLe SoLUTIon

ProBaBLe caUSe

After the actuator goes to full fuel, disconnect the speed sensor at Terminal

C & D. If the actuator is still at full fuel-speed then the speed control unit is

defective.

If the voltage reading is 1.0 to 2.0 V DC:

•

SPEED adjustment is set above desired speed

•

Defective speed control unit

If voltage reading is above 2.0 V DC then check for:

•

actuator binding

•

linkage binding

If the voltage reading is below 1.0 V DC it may be a defective speed

control unit

Check if Gain is set too low.

•

Speed adjustment set too high.

•

OVERSPEED set to close to running speed.

•

Actuator or linkage binding.

•

Speed control unit defective.

OVERSPEED set too low. Adjust 5-6 turns CW.

Erroneous speed sensor signal. Check wiring.

If voltage for a 12 V DC system is less than 7 V DC, or for a 24 V DC system is

less than 14 V DC, replace the battery if weak or undersized

•

Actuator or battery wiring in error

•

Actuator or linkage binding

•

Defective actuator

•

Fuse opens. Check for short in actuator or harness.

If voltage measurement is within 2 V DC of the battery supply voltage level,

then fuel control is restricted from reaching full fuel position, possibly due to

mechanical governor, carburetor spring, or linkage interference.

SPEED parameter set too low

ESD5550-5570 Series Speed Control Unit 9-2020-E PIB1003